A slider (magnetic head) used to read/write data on a medium such as a magnetic disk is installed in an actual device after rotating a medium and testing the float characteristics above the medium surface and a read/write function for data on the medium. Conventionally, the functions of a slider have been tested by installing the slider on a suspension to form a slider assembly and setting the slider assembly in a tester.
However, when the fraction defective for sliders is high, the suspension will be discarded together with the slider, and therefore there is the problem that the manufacturing cost of the suspension and the cost of assembling the slider assembly are wastefully incurred in addition to the manufacturing cost of the slider. For this reason, a method of testing the functions of a slider as a single body before mounting on a suspension and mounting only non-defective sliders on suspensions has been considered.
FIG. 7 shows an example construction of a slider tester for testing the characteristics of a slider as a single body. Reference numeral 10 designates the tester main body of the slider tester. The tester main body 10 includes a driving unit that rotates a test medium 12 in the same way as in an actual device, a movement control unit for moving the medium 12 to a test position where a slider is set, and an investigation apparatus for investigating the data read/write characteristics for the combination of the medium 12 and the slider at the test position.
The slider tester in the illustrated example is provided with setting units where sliders 14 that are the tested products are set at four corners of the upper surface of the tester main body 10. The setting units respectively include a set plate 20 that supports a slider 14, an arm part 22 that supports the set plate 20, and a mounting base 24 that supports the arm part 22.
The medium 12 is supported on a spindle 13 so that the medium surface is horizontal. The spindle 13 is provided so as to be movable from one side of the tester main body 10 to the other, and by moving the medium 12 supported by the spindle 13 from one side of the tester main body 10 to the other, it is possible to test the respective sliders 14 set on the set plates 20.
FIG. 8 shows a slider attaching construction for attaching a slider 14 onto a set plate 20. The set plate 20 includes a ring spring 30 for supporting the slider 14 in a floating state with respect to the surface of the medium 12, a socket 40 for detachably supporting the slider 14, and a pressing mechanism 50 for elastically pressing the socket 40 to apply a predetermined load to the slider 14. It should be noted that the ring spring 30 and the socket 40 construct a movable support part that can movably support the slider 14.
In a state where the slider 14 is supported by the socket 40, the ring spring 30 supports the slider 14 so that the slider 14 can be tilted in freely chosen directions (in a pitching direction and in a rolling direction). The ring spring 30 is formed by providing arc-shaped slits in a thin metal plate so that the slider 14 can be tilted in the freely chosen directions. The socket 40 is joined to a lower surface of a setting part 34 formed in the center of the ring spring 30. A contact block 42 and a pressing spring 48 that faces the contact block 42 are provided on the upper surface of the socket 40. By elastically pressing the slider 14 toward the contact block 42 using the pressing spring 48, the slider 14 is set with the terminals of the slider 14 pressed into contact with contact terminals provided on the contact block 42. The contact terminals of the contact block 42 are electrically connected to the investigating apparatus via a wiring pattern provided on the ring spring 30 and the electrical characteristics of the slider 14 are measured.
The pressing mechanism 50 includes a pressing pin 51 disposed below the socket 40 and a coil spring 52 provided so as to push out the pressing pin 51. The coil spring 52 causes an upper end surface of the pressing pin 51 to contact a lower surface of the socket 40 to elastically press the slider 14 supported on the ring spring 30 toward the medium surface. By adjusting the energizing force of the coil spring 52, it is possible to adjust the load that acts on the slider 14 and therefore the float of the slider 14 with respect to the medium surface can be adjusted.
By doing so, it is possible to set the sliders 14 on the set plates 20, to cause the sliders 14 to float with respect to the medium in a state where the test medium is rotated, and to carry out read/write tests for data. According to this slider tester, it is possible to test the characteristics of sliders as single bodies before mounting on a suspension, and therefore it is possible to avoid the wasted manufacturing cost and assembly cost described above.
However, in the slider tester according to the construction described above, since the pressing spring is fabricated using a metal plate spring, there has been the problem of the spring being susceptible to deterioration and the problem that it is not possible to replace the pressing spring without dismantling the assembled components.
In addition, sliding resistance is produced by the pressing mechanism guiding the pressing pin, and therefore there has been the problem that the load applied to the slider fluctuates and the floating posture of the slider becomes unstable.
The present invention was conceived to solve the problems described above and it is an object of the present invention to provide a highly reliable slider tester that is easier to maintain due to the pressing plate being easily replaceable, that can prevent fluctuations in the load that acts on the slider, and that can correctly test a slider as a single body.